Wax coated paper



Patented June 29, 1937' p i UNITED STATES PATENT OFFICE WAX COATED PAPER Clarence M. Loane, Whiting, and Bernard H. Shoemaker, Hammond, Ind., assignors to Standard Oil Company, Chicago, 111., a corporation of Indiana No Drawing. Application February 7, 1936,

' Serial No. 62,808

7 Claims. (Cl. 91-68) This invention relates to an improvement in the ess, paraflin wax having a melting point of 126- manufacture of wax coated papers and specifi- 130 F. may be heated with chlorine in a glass cally to papers which are coated with paraffin wax lined vessel until the amount of chlorine absorbed in which the melting point of the wax employed by the wax reaches 10 to 15%. The resulting lies between 120 F. and 145 F. An object of the chlorinated wax may then be mixed with about invention is to improve the appearance of wax of its weight of naphthalene and to the coated papers, especially with respect to gloss and melted mixture at a temperature of 150 to 400 F. transparency. Another object of the invention is there is added with vigorous agitation 5 to 10% of to improve the sealing properties of the wax anhydrous aluminum chloride. The reaction 10 coated papers. Other-objects will be apparent proceeds rapidly and within 30 minutes the reac- 10 from the following description of the invention. tion is substantially complete. The reaction mix- In the coating of paper with paraiiin wax, it is ture is then Washed with water and neutralized, a common practice to pass the paper through a hydrocarbon diluent being added at this stage to bath of melted paramn and regulate the amount facilitate handling the heavy condensation prodof parafin allowed to remain on the paper by ucts. A suitable diluent may be naphtha, kero- 15 suitable wipers and rollers. Thetemperature of sene or other light hydrocarbon oil. After neuthe wax bath also has an effect in determining tralization it is preferred to remove the diluent by the amount of wax remaining on the paper. In distillation, leaving the Wax condensation product general, there are two kinds of waxed paper in a form suitable for adding to the paper coating known to the trade: one called dry waxed paper; composition. If desired, melted paraffin wax may and the other wax coated paper. The wax be used as the diluent, in which case it is added coated paper usually contains about 50% more immediately after the completion of the condenwax than the dry waxed paper which does not sation reaction. When washing and neutralizing contain suificient Wax to present a glossy surface. the product in this case it is necessary to keep the This invention is concerned more particularly temperature of the product above the melting with the waxed papers of the coated type. The point of the wax at all times to maintain it in amount of wax in a dry waxed paper may be liquid condition. When using parafiln wax as a ordinarily about 5 to 8 pounds per ream of 20 diluent, 1 to 5 volumes of wax may conveniently pound weight, whereas the wax coated paper will be employed and the step of removing the diluent usually contain from 10 to 14 pounds of wax for may beomitted, the wax-containing product being 30 the same amount of paper. added directly to the paper coating composition.

We have discovered that wax coated paper is We may also prepare our wax condensation prodgreatly improved by incorporating in the wax beuct from a less highly chlorinated wax, e. g., Wax fore applying it to the paper a relatively small containing only 5% chlorine, in which case the amount of a material which will hereinafter be unchlorinated wax passes through the condensa- 35 referred to as a wax condensation product. tion reaction unchanged and appears in the final This wax condensation product is produced by the wax coating composition. I condensation of parafiin wax-with aromatic mate- In an alternative method of making the wax rial, especially aromatic compounds such as bencondensation products, the aromatic material, for

40 zene, toluene, xylene, naphthalene, anthracene, example, naphthalene or toluene, may be mixed 4 anthracene residues, diphenyl, etc. Wax condenwith the aluminum chloride catalyst and the sation products of the type herein employed are chlorinated paraflin added gradually with efficient described in U. S. Patent 1,963,917, filed January agitation. The color of the product by either 18, 1933. The method of manufacturing the wax method may be improved by filtration through condensation products may be varied considerfullers earth. 45 ably, it being essential that the wax be activated In preparing our wax coating composition we a by chlorination or other treatment such as dehymay add from to 25% of wax condensation drogenation, and thereafter condensed with the product to the paraflin wax employed for coataromatic material in the presence of a suitable ing the paper, although we prefer to employ from catalyst of the Friedel-Kraft type such as anhy- 2 to 10% for most purposes. It is suflicient to 50 drous aluminum chloride or other active metal thoroughly mix the wax condensation products halides such as anhydrous zinc chloride, boron with the melted paraffin wax. In a typical coattrifluoride, or aluminum-sodium chloride. ing operation we have employed a composition As an example of one method of making the prepared by mixing 5% of the wax condensation wax condensation products employed in our procproduct with refined paraflln wax having a melt- 55 carefully compared with paper was applied was a typical wood pulp paper such used for the wrapping of bread The coated paper was coated with the same kind of paraflin wax as used in the coating composition of this invention but without the addition of the wax condensation product. The comparison showed a very distinct improvement in the gloss and feel of the improved wax paper and the transparency was also considerably greater. The coating was firmer and showed less tendency to be removed by scraping. The paper was also more readily sealed by the application'of as is commonly and other food products.

heat, giving a more uniform and stronger seal than in the case of the paper coated with paraflin wax alone.

Although we have described our invention in respect to specific applications thereof, it should be understood that the scope of the invention will be determined by the following claims construed as broadly as the prior art will permit.

We claim:.

1. The improvement in wax coated papers comprising a sheet of paper impregnated with paraiiin wax containing a relatively small proportion of a condensation product of chlorinated paraffin and an aromatic hydrocarbon.

2. The improvement in wax coated papers comprising a sheet of paper impregnated with rating in the parafiin wax paraffin wax containing from to 25% of a condensation product of chlorinated paraflin and an aromatic hydrocarbon.

3. The improvement in wax coated papers comprising a sheet of paper impregnated with paraflin wax containing from 2% to 10% of a condensation product of chlorinated parafiin and an arcmatic hydrocarbon.

4. The improvement in coating compositions for wax coated papers comprising paraflin wax having a melting point within the range of from to F., incorporated with from to 10% of a condensation product of chlorinated paraflin and an aromatic hydrocarbon.

5. An improved waxed paper characterized by a high gloss and high transparency, comprising .a sheet of paper impregnated with paraffin wax incorporated with 2% product of chlorinated parafiin and an hydrocarbon.

"6. The process of increasing the transparency and gloss of waxed paper, comprising incorporating in the paraflin wax before applicationto said paper a condensation product ofchlorinated paraffin wax and an aromatic hydrocarbon.

7. The process-of increasing the transparency and gloss of waxed paper, comprising incorpobefore application to said paper a condensation product of chlorinated paraflin wax and naphthalene. I

to 5% of a condensation aromatic CLARENCE M. LOANE. BERNARD H. SHOEMAKER. 

